I’ve published ten posts on my blog so far and all of them are based on scientific journal articles. But I also want to occasionally post some interesting and fun science facts so I have put together this amazing list. Hope you have a glowing New Year!
Among all the types of carnivorous plants, snap traps—represented mainly by the iconic Venus flytrap—have fascinated us for centuries. Even Darwin was mesmerized by the plant describing it as “one of the most wonderful in the world.” After all, when do we get to see plants actively “hunting” for insects? It is the Venus fly trap that reminds us that plants are really alive—and can also be murderous.
Only two plants have evolved into snap traps. The first, of course, is the Venus flytrap, also known as Dionaea Muscipula, and is found only in the coastal bogs and swamps of North and South Carolina, USA. The second one, believed to be its close descendent, is the waterwheel plant, Aldrovanda vesiculosa. As its name suggests, it is an underwater plant that grows in shallow acidic waters of wetlands in central Europe, East Asia, Africa, and Australia.
As mentioned in Part One, carnivorous plants grow in nutrient-poor areas—especially those devoid of nitrogen—and this is why they have resorted to carnivory in the first place.
Contrary to our expectations, the Venus flytrap is actually quite small. The entire plant can reach about 13 cm (5 inches) in diameter while traps are usually about 2.5 cm (an inch) in length but can reach to a maximum of 5 cm (2 inches)—far from the monstrous image we have of traps devouring large prey. Under moderate conditions, a single plant can have 4 to 8 traps; if conditions are great, trap numbers can soar up to 20 per plant.
If you thought that was small, the traps of the waterwheel plant tiny. Each leaf trap, which grows in whorls along the main stem, is only 2 to 7 mm in length—about the length of a corn kernel. The main stem of this rootless, floating aquatic plant can grow more than a foot long.
You might wonder how a plant “hunts” for prey. Why would a bug flying far away want to visit the Venus Fly Trap? It turns out that the Venus flytrap attracts insects from distant locations by releasing volatile scents mimicking those emitted by fruits and flowers. Scientists found that fruit flies are lured towards the plant because of odors emitted that mimicked ripe and rotten fruits—their natural food source. As a result, scientists believe that hungry insects—particularly flies—are duped into visiting the plant in anticipation of a tasty meal.
The rims of the reddish inner surface of the two lobes of the trap also secrete nectar and insects are fooled into thinking they have visited a flower.
How the Venus Fly Trap Works
The trap is actually a modified leaf split into two lobes with teeth-like spikes jutting out from the margins. Inside each lobe, three or four short hair-like projections are displayed. These hairs play a role in detecting prey. When insects land on the hairs, the mechanical stimulation triggers the claw-like lobes to snap shut, enclosing prey inside it.
Trap closure is elegantly regulated to prevent it from accidentally shutting from a false alarm rather than real prey. The lobes only close when prey touches its hairs twice within a span of 25 to 30 seconds. It won’t close when hit by falling raindrops, blasts of air, or a gentle brush of a bug passing by.
Scientists have been intrigued by what it takes to close the trap. Researchers have stimulated trap closure by touching the hairs with cotton thread, applying electrical currents and chemicals, and even poking their fingers.
Touching of the hairs triggers closure by activating mechanosensitive ion channels. Once these channels are activated, an action potential, which is an electrical signal, is generated that propagates through the upper leaf of the Venus flytrap. It takes two action potentials within 30 seconds for the lobes to rapidly shut and enclose the victim.
Remarkably, it takes only a tenth of a second for the lobes to shut—faster than the time it takes for you to blink your eye! No wonder it is one of the fastest movements in the plant kingdom.
Watch this video compilation of Venus fly traps catching flies and other crawling bugs.
The movement we see is actually caused by a change in the curvature of the lobes, flipping from curved outward in a convex shape to inward in a concave shape—like flipping of a contact lens—so as to enclose prey. The open state or convex shape of the leaf trap stores elastic energy because of differences in water pressure between the outer and inner layers of the lobe. Once a bug stimulates the hairs, electrical signals trigger the opening of water pores causing water to rapidly rush between the two layers in the lobes, and the lobes close relaxing in an equilibrium state. This process is known as snap-buckling instability.
The lobes exert considerable constriction force—up to 4N, equivalent to almost one pound—which is difficult for most prey to overcome.
Once closed, they may open only after 5 to 12 days after the prey has been digested. The opening of the trap is much slower because it requires energy for the plant to pump water from one layer of the lobe to the other. It also depends on how large the prey is, age of the trap, and the air temperature.
During closure, the digestive zones of the traps lower photosynthesis and have to increase respiration to meet the energy demands.
The traps can only last a couple of times before they become unusable.
The interlocking marginal teeth at the lobes of the Venus flytrap help to retain prey. But small prey can still escape from the gaps between the teeth. Darwin hypothesized that the teeth allow small prey to escape so that the plant doesn’t waste energy in closing its trap for many days to digest a tiny insect with few nutrients. One very old study (from 1923) analyzing the sizes of prey caught by the traps provides some support to his theory. However, no recent studies have been conducted investigating this theory.
The Venus flytrap mostly captures walking prey such as spiders, ants and beetles as opposed to sticky traps, which mainly capture flies.
How the Waterwheel Trap Works
The waterwheel plant, which is closely related to the Venus flytrap, grows underwater and consists of almost transparent clam-like traps with two lobes curved toward each other so they can quickly close when prey enters. As mentioned earlier, the leaf traps grow in whorls of about seven or eight leaves per node where each leaf trap consists of 2 lobes up to 7 mm long—about the length of a corn kernel. Compared to the Venus flytrap, the traps have not been studied much, because they are hard to grow and tiny.
Like the Venus flytrap, the inside surface of the lobes also have tiny trigger hairs—about 20 in each lobe—that can sense tiny aquatic critters like zooplankton. But unlike its cousin, the mechanism of trap closure is completely different: the lobes do not change curvature by inverting. Instead, the area around the midrib—that joins the two lobes together—bends inwards when closing. Scientists believe that the opening and closing is caused by swelling and shrinking of the cells around the midrib. The lobes close as fast as the Venus flytrap—taking only a tenth of a second.
Here is a video of A. vesiculosa in action
Digesting the Kill
Upon capture, further movement of the insect prey in Venus flytraps stimulates the hairs and causes the two lobes to seal tightly forming a “green stomach.” The sealing is stimulated by two touches of the hairs, which trigger the production of a hormone called jasmonic acid, which in turn signals the production of digestive enzymes. In non-carnivorous plants, this hormone is involved in defense against herbivory. This tightening and sealing phase takes at least half an hour. Sealing has many purposes: it prevents prey from escaping, ensures that digestive enzymes don’t spill out, and that nutrients released from digestion are not lost.
Inside the trap, the struggling prey tries to escape and in the process ends up touching the trigger hairs again and again—for the third, fourth, fifth time, and so on. These subsequent touches activate the firing of many more action potentials, which travel throughout the trap, and last for hours after capture. Experiments have shown that insects are alive for up to 8 hours inside the trap.
The video below is a time-lapse of a one-hour long video. You can see the flipping of the lobes upon closing. Also, you may notice how the left trap continues to vibrate after closing as the fly struggles to escape and as it does so the lobes continue to seal tightly.
The plant “counts” these action potentials to control the amount of digestive enzymes produced. More than three touches trigger the production of digestive enzymes from the thousands of gland cells lining the inside surface of the lobes. These glands secrete digestive fluids and also “suck up” the digested nutrients. The cocktail of digestive enzymes include chitinases to break down chitin, a component of insect exoskeletons, proteases for protein breakdown, and nucleases for DNA digestion, among others. All of these enzymes turn the insect prey into goo for easy absorption.
Many of the enzymes produced during digestion are similar to those produced by Nepenthes pitcher plants. These enzymes are produced by non-carnivorous plants to defend against an attack by microorganisms. Scientists think that these defense-related enzymes evolved to digest prey, although they may still provide protection against microbes during digestion.
The number action potentials fired helps the plant gauge the size and nutrient content of prey. More action potentials tell the glands to prepare for large prey by ramping up production of prey-degrading digestive enzymes and ion channels for subsequent nutrient uptake. Fewer action potentials mean smaller amounts of digestive enzymes are produced.
Because digestive enzymes are energy-intensive for the plant to produce—requiring expensive nutrients like nitrogen—it has evolved to ‘count’ the touches by an insect and produce them only when a catch is confirmed—saving energy from unnecessary production due to a false alarm.
When the lobes open after digestion, whatever left of the insect is blown away by the wind.
Origins and Evolution of Snap Traps
Molecular studies have shown that snap traps have evolved only once at least 65 million years ago in the Old World. These studies revealed that snap traps have evolved from Drosera, the sticky traps. As sticky traps tend to capture small prey, the Venus flytrap is thought to have evolved to capture and digest larger, more nutritious prey. The Venus flytrap and the Waterwheel plant both have high rates of gene substitution compared with sticky traps suggesting the transition from sticky traps to snap-traps might have been quite rapid.
But exactly how they evolved is a mystery because they are no intermediate fossils. Scientists suggest that the tentacles of sticky traps evolved into the trigger hairs and the claw-like teeth on the margins of the lobes. The sticky glands at the tip of the tentacles in Drosera are thought have turned inward into digestive glands inside the lobes of the Venus flytrap.
Some Drosera plants possess striking speed of prey capture akin to snap traps. The long marginal snap-tentacles in D. glanduligera respond rapidly to touch by flinging insects at the edges into the middle of the trap. It is thought that these are pre-adaptations, particularly the fast snapping action of tentacles, leading to the evolution of snap traps.
Both of these amazing species of snap traps face numerous threats. Historically, both the Waterwheel plant and the Venus flytrap were more abundant as well as widespread throughout the continents.
In the last century alone, Waterwheel plant populations have declined drastically in Europe and remaining populations are small and fragmented. Millions of plants were introduced in the Eastern US, and appear to be thriving. The Waterwheel plant is classified as endangered by the IUCN (International Union for Conservation of Nature), with a major threat being a global decline in wetlands, its natural habitat.
Although the Venus flytrap is not listed as endangered by the IUCN or the Endangered Species Act in the US, the plant is rare, even in its natural habitat. Today, the plants are only found on lands owned by the government, US military, and The Nature Conservancy, a conservation organization.
Land development, fire suppression (fires help clear out shrubs and other big plants that block sunlight for the Venus flytrap), and poaching means Venus flytraps now inhabit less than 10 percent of the area than they used to. They are restricted to an area of 120 km around Wilmington in North Carolina.
The plant’s popularity among cultivars is threatening its existence. Poaching and over-collection are common involving thousands of plants at one time. Because the Venus flytrap has shallow roots, poachers remove the traps and uproot the bulb; they can fit more than a hundred of the root bulbs in their hands.
Until recently, poachers only faced a small fine of $50. But the good news is that a new law enacted from December 2014 makes it a felony to pluck plants from the wild and poachers face a minimum jail time of 25 months—along with fines. In January 2015, four men—carrying 970 plants—were the first to be arrested and charged for poaching Venus flytrap plants under the new law.
The Nature Conservancy is educating the public about the uniqueness of the Venus flytrap because people from around the world flock to North Carolina just to see Venus flytraps. They are also working on finding alternative earning methods for potential poachers.
Inspired by the Venus flytrap, scientists have designed robots mimicking the snapping lobes of the trap. In 2004, a team from the Bristol Robotics Laboratory, UK developed Ecobot, a robot that uses bacteria to digest bugs, food, and other waste matter like sewage. Digestion makes electrons available to generate electricity. But it cannot attract and catch prey on its own so the researchers fed it with dead flies. It ran for a stretch of 12 days after being fed with 8 houseflies.
In a more recent attempt, a researcher developed a robotic trap made of polymer membranes with added metals joined together with an electrode in the middle that acts like a spine—resembling the midrib of the trap. Both membrane lobes have 15-20 bristles that are facing each other, which act like trigger hairs sensing a bug and send a signal for the polymer lobes to bend toward each other and close. When a bug lands on the bristle, a small voltage is produced that triggers a larger power source to create opposite charges on the lobes, attracting them towards each other to close. The bristles are placed at angle facing inwards so that when the lobes close, they will interlock.
Nuclear-Waste Clean Up
The trap mechanism has inspired scientists to create a method which captures radioactive cesium ions, instead of bugs, in the clean-up of nuclear waste. Liquid nuclear waste contains a large concentration of sodium ions, which are harmless, but only a small concentration of cesium ions. This is why removing the cesium is difficult.
Scientists devised a new sulfide-based synthetic material composed of tiny holes to allow cesium ions to pass through the material. The cesium ions are attracted to the sulfur atoms in the material triggering a change in the shape of the material, which shuts its pores, trapping the cesium ions and preventing them from escaping—akin to the Venus flytrap. The material was reported to able to capture up to 100 percent of the cesium ions in solution.
Learning about how snap traps work makes me appreciate them even more. It is no wonder that Darwin was fascinated with these plants: They are truly marvels of evolution. We still have a lot more to learn about these bizarre plants. But after reading this post, I’m sure you would agree that not all plants are boring.
Bohm et al., (2016). The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake, Current Biology, 26, 1–10.
Ellison, A.M. and Gotelli, N.J. (2009). Energetics and the evolution of carnivorous plants—Darwin’s ‘most wonderful plants in the world’, Journal of Experimental Botany, Vol. 60, No. 1, pp. 19–42.
Gibson, T.C., and Waller, D.M. (2009). Evolving Darwin’s ‘most wonderful’ plant: ecological steps to a snap-trap, New Phytologist, 183: 575–587.
Kreuzwieser et al. (2014). The Venus flytrap attracts insects by the release of volatile organic compounds, J Exp Bot. 2014 Feb; 65(2): 755–766.
Libiaková, M., Floková, K., Novák, O., Slováková, L., & Pavlovič, A. (2014). Abundance of Cysteine Endopeptidase Dionain in Digestive Fluid of Venus Flytrap (Dionaea muscipula Ellis) Is Regulated by Different Stimuli from Prey through Jasmonates. PLoS ONE, 9(8), e104424.
Pavlovic A., Demko V., and Hudak, J. (2010). Trap closure and prey retention in Venus flytrap (Dionaea muscipula) temporarily reduces photosynthesis and stimulates respiration, Annals of Botany 105: 37–44.
Poppinga S., and Joyeux M. (2011). Different mechanics of snap-trapping in the two closely related carnivorous plants Dionaea muscipula and Aldrovanda vesiculosa. Phys. Rev. E 84, 041928.
Shahinpoor, M. (2011). Biomimetic robotic Venus flytrap (Dionaea muscipula Ellis) made with ionic polymer metal composites. Bioinspiration & Biomimetics, 6, 046004.
Volkov, A.G., Coopwood, K.J., and Markin V.S. (2008). Inhibition of the Dionaea muscipula Ellis trap closure by ion and water channels blockers and uncouplers. Plant Science, 175(5):642-649.
Volkov et al. (2013). Venus flytrap biomechanics: Forces in the Dionaea muscipula trap. Journal of Plant Physiology, 170(1):25-32.
Volkov A.G., Forde-Tuckett V., Volkova M.I., Markin V.S. (2014). Morphing structures of the Dionaea muscipula Ellis during the trap opening and closing. Plant Signaling & Behavior, 9:e27793.
My grandmother passed away a few years ago. She had few possessions: only one suitcase full of clothes and a cabinet of dishes.
I thought about how many possessions I had and came to the shocking realization that all my stuff would fill at least five large suitcases. That is when I thought: How many things do I actually use on a daily basis from all the stuff I have? I struggled to think of more than ten items, yet my home is filled to the brim with all kinds of paraphernalia. I felt rather disturbed and guilty when I realized I’ve been hoarding so much stuff for all these years without actually using it.
If just one person among the billions on Earth has enough stuff to fill several suitcases, what about the rest of the world? We now have more than 7 billion people on Earth — growing by about 75 million per year; there are more mouths to feed, more people to house, and clothe than ever before. Demand is severely straining nature’s already limited resources. Our carbon footprint, which refers to our total greenhouse gas emissions, has shot up 11 times since 1961.
As a species, we are exterminating countless other species we share our planet with, many of which we didn’t even know existed. Over the last century, we have lost vertebrate species at a rate 100 times higher than the natural rate — and this is a conservative estimate. Sadly, the sixth “mass extinction” is already underway.
We are also living longer. A study I covered on my blog in 2013 found that countries with a high life expectancy were associated with more endangered and invasive species of birds and mammals. The reason, the authors postulated, was that as people live longer, they consume more resources — like food, water, and gas — and thus their carbon and ecological footprint is greater. Ecological footprint refers to how much area of biologically productive land and water an individual, population or activity requires to produce all the resources it consumes and to absorb the waste it generates.
If we look at the ecological footprint per person for each country compared with the biocapacity of the country per person we can get an idea of the how strained the environment is with respect to consumption levels. In 2011, the ecological footprint for the US ranked third highest in the world at 6.8 global hectares per person while its biocapacity was only 3.6 global hectares per person meaning Americans were consuming almost twice as much as their environment can provide. Using the global average biocapacity, which is 1.7 global hectares available per person, Americans were consuming four times more resources than their environment would provide. In other words, four Earth’s would be needed if everyone in the world lived the American lifestyle.
In comparison, China’s ecological footprint stood at 2.5 global hectares per person (global ranking at 62), which is almost three times higher than its biocapacity per person, and 1.5 times higher than the global average. India, which has a similar population to China, but three times smaller land area, had an ecological footprint of 0.9 global hectares per person (global ranking 128) — two times higher than its biocapacity but only half of the global average biocapacity.
One of the greatest paradoxes of our modern world is that we want to constantly raise economic growth because it is the standard measure of how well a country is doing. But our environment is inevitably destroyed in the process; chopping down trees to make more land available for industries and crops, extracting more raw materials from our Earth to produce all the stuff we consume, and drilling for more oil to meet our burgeoning energy demands are just some of the ways we plunder our Earth.
As humans, we mostly consume resources rather than provide any real benefit to nature. Nature doesn’t really need us, but we need nature. Excessive growth will eventually cause our own decline because our well-being is inextricably tied to the health of the Earth’s ecosystems.
Lured by the array of products on offer and slick advertising, people often get carried away into buying many more products than they actually need — most of which end up in a closet never to be seen again. As a teenager, I, like many others, succumbed to the excessively materialistic lifestyle that is prevalent in society. Shopping became a pastime, something that you do with your friends. The path towards materialism is sowed from childhood; children are swamped with all kinds of plastic toys and gadgets to play with.
And while consumers are now becoming more conscious of the products they are buying, and where they come from, few think about what happens to them when they reach the end of their life.
Do you know where your toothbrush comes from? How much energy went into producing it? Where will it end up after you trash it? How many toothbrushes have you used so far in your life?
Recall all the products you use in a day, from the moment you wake up, till the end of the day, and all the materials involved in manufacturing these products such as plastic, metal, and paper. Think about all the energy that goes into producing a single product from processing of the raw materials to assembling, packaging, and transportation to the store.
Throwing away these products without using them means that all the energy expended in producing them is wasted — that is, gone forever. Moreover, all products have a limited life, and disposal is another problem as much of the stuff we throw ends up in landfills.
I now realize all the stuff I bought or yearned to possess over my lifetime seem so trivial. Knowing how much energy was consumed in producing these things, I felt ever so guilty and vowed to myself that I won’t ever stash so much stuff again.
The rise of China’s upper class has led to an insatiable craving for “hongmu” or rosewood furniture, leading to swathes of forests being illegally cut down in Myanmar, Indonesia, and other South East Asian countries — even as far as Madagascar. China has yet to ban illegal wood imports as it wants access to cheap wood.
Land bulldozing and slash and burn farming for paper and palm oil plantations by companies and farmers is threatening the already endangered orangutan populations. Needless to say, many of the snacks we buy from our local supermarket contain palm oil. Alarmingly, more than half of Indonesia’s greenhouse gas emissions are caused by these fires. The haze generated from illegal forest fires in Indonesia, which continue to rage as I write, affects the entire South East Asia region causing respiratory diseases in thousands of people.
Our plastics are choking the oceans and over 90% of seabirds have ingested plastic at some point in their lifetime compared with less than 5% in the 1960s. Even sea turtles have not been spared. In a study last year, Qamar Schuyler, a postdoctoral fellow from the University of Queensland, recovered large amounts of plastic debris from dead stranded sea turtles.
“A lot of the plastics that turtles are consuming are end-user items, such as packaging and food storage materials. We all need to be more responsible and aware of our choices and reduce the amount of these consumer items that end up in the waste stream,” said Schuyler.
Illegal poaching for elephant ivory has reached epic proportions: more than 100,000 African elephants were slaughtered from 2010 to 2012 — that’s around 91 elephants killed per day over three years. The driving force behind the massacre is demand from China and other parts of Asia, where ivory products are perceived as items of good luck and as status symbols. As consumers we need to ask ourselves: Do we really need ivory? Can we live a happy and fulfilling life without using ivory products?
Even the noise generated by container ships — which transport many of the modern goods we use — makes young critically endangered European glass eels more stressed and less likely to fend off predators, according to a study I covered last year on my blog.
Living in Moderation
Climate change is very much in our control and this is where sustainable development comes in. Sustainable living and “going green” are buzzwords these days. While transitioning to renewable energy sources is a definitely a start, a long-term solution boils down to changing our consumption patterns, our habits, and our lifestyles.
Every choice we make to buy a commodity has an impact on our planet, from the quantity and type of products you use on a daily basis, to the materials that went into producing them.
So what does it mean to be sustainable? The art of sustainable living, as I call it, lies in embracing moderation and restraint in our lives. This means reducing our dependence on products and using fewer products to achieve our goals. If we can manage with fewer products this will lead to less waste. What we need to exercise is moderation in consumption.
Quality of life isn’t measured by how many possessions you own or how valuable they are. You can live a high quality and fulfilling life with few possessions; it is all about the choices we make. As children, my parents didn’t have many toys and yet they were content.
We have to transcend the appeal of possessing things and look into their value, their utility. How many times do we use a product until it reaches the end of its life cycle? For some, it is only once, while others can last several months to many years. For example, kids get bored of toys pretty quickly these days. Many toys are made of plastic and also contain hazardous metals. Sooner or later, they are dumped into landfills.
While all consumption is indirectly detrimental to our environment, we can reduce the impact by keeping a tight rein on our wants. Ideally, parents should instill the art of moderation in their children from a young age.
How can we lead a life that will have the least impact on the environment?
Whenever buying anything — from clothes, shoes, and bags, to books, electronic appliances, gadgets, and household items— I ask myself the following:
1. Do I really need this? Can I do without it?
2. How many times will I actually use it?
3. How long will it last?
4. What will I do with it once I’m done using it or once it has reached the end of its life cycle? (Think: can I recycle it? Can I donate it to someone who can use it? Is it just going to end up in the trash?)
I go through these questions in my mind rather than just looking at whether I like the product and the price. If we go through these questions we can try to eliminate purchases which weren’t really necessary in the first place.
The key is to buy only what you really need; resist the temptation to buy items just because they are on sale and think twice before buying something. If you will only use something once, after which it ends up in a closet or drawer never to be seen again, not only have you wasted your money, but no one else can use the product either. And if it cannot be used by anyone else, it becomes waste.
Don’t get me wrong here; I don’t mean to abstain from all purchases. Moderation is the key, just like we exercise restraint when eating rich or fatty foods. Of course, occasionally you will buy something that you have been planning to buy and will use for a long time.
You need to reflect on why you are buying something in the first place. Are you buying things to maintain a certain image, to please others, to make yourself happy or some other reason? If it is for personal pleasure, I have found that happiness doesn’t last long and when the euphoria wanes, you won’t know what to do with all the stuff you’ve accumulated. It’s a cycle: you are dying to buy a product, you spend all your energies to obtain it, you get bored of it, you chuck it away, and then you yearn for something else to satisfy yourself.
Like all living things, our bodies will one day return to the Earth. The indelible mark we will leave on Earth will be our carbon and ecological footprints.
Who had the lowest footprint and yet lived a fulfilling life? Wouldn’t it be so gratifying to look back in your final days on Earth knowing that your existence was not a large burden on our environment? And that you only consumed what you needed with the least amount of waste.
As for me, I haven’t bought much in the past few years — hardly any clothes, shoes, bags, etc — and I’m still working on reducing my stuff. I’ve managed to cut down one suitcase, but I still need to clear out a few more suitcases of clutter, after which I will feel so much lighter and free. I now realize that less is truly more.
I end with Mahatma Gandhi’s renowned quote, which I believe we all need to accept and act upon.
Earth provides enough to satisfy every man’s needs, but not every man’s greed.
If you thought pitcher plants were cool, enter the amazing world of sticky or flypaper traps. These traps are dominated by the genus Drosera, commonly known as the sundews, representing more than 180 species. They are the only genus of active sticky traps, which are most interesting because they often feature moving leaves, and are found in all continents except, of course, Antarctica.
Humans have always been in awe of birds: their beautiful feathers, their graceful flight, and their sweet songs. These are just some of the features that distinguish them from other animals. Birds are extremely diverse—with over 10,000 living species on Earth—and are found in all kinds of environments, from extremely hot and dry deserts, to the frigid Antarctic.
Penguins are particularly interesting for scientists as they are flightless birds that can swim and have evolved to thrive in the hostile Antarctic environment where few animals can survive. Now, we are a step closer to understanding their evolutionary history, population sizes in response to historical climate change, as well as the genes involved in their ability to adapt to such extreme climates, with an exciting new study published last month in GigaScience, an online open-access BGI-BioMed Central journal.
Plants are boring. At least that is what I—as well as countless others—thought in school. Animals seemed far more exciting than studying plants. In hindsight, I wonder why I didn’t find plants interesting. One of the reasons was that I couldn’t see plants moving—with the exception of ‘touch-me-nots’ that rapidly fold inward upon touching—and they aren’t cute and cuddly as mammals are. Later, when I learned that plants produce their own sugars using water, carbon dioxide, and sunlight—a phenomenon we know as photosynthesis and achieved by only a few other life forms— I got a little interested.
But what really piqued my curiosity and captivated me was when I learned that some unusual plants go a step further: they have evolved to ‘eat meat’—insects in particular. We normally expect insects to eat plants, which in turn are preyed on by larger animals, as the food web goes. But when the roles are reversed, it is harder for us to digest that plants can actually play the role of predators.
Noise pollution in the ocean isn’t just a nuisance; it has grave consequences for the survival of some marine organisms. A recent study reveals that ship noises make young eels stressed and when confronted with predators, they are less likely to fend off attacks due to impaired escape behaviors, known as antipredator responses.
During exposure to harbor ship noise, young eels were less responsive when faced with a looming predator and showed slower escape behaviors than eels exposed to sounds of the harbor only. And when pursued in a simulated predator chase, they were caught faster than eels exposed to harbor-only sounds.
While humans have explored the oceans for centuries, ship traffic now is greater than ever before, largely because of international trade. Commercial shipping activity—transporting the myriad of consumer goods we have become increasingly reliant on—pervades the oceans. Many of the goods transported by ships may make our lives easier, but these unfamiliar man-made noises can pose a threat to marine organisms. In some cases, the effects could mean the difference between life and death.
Sharks, the ocean’s top predators, renowned for their impressive hunting abilities, rely extensively on their keen sense of smell to hunt prey located miles away—earning themselves the label “swimming noses.” But a new study reveals that high levels of seawater acidity expected due to climate change can diminish their ability to track prey through sensing of odors.